Rails - Jun 2006 - options vs. html options in collection_select

I wanting to add an onchange event handler to collection_select but I''m
not
sure how.

The api gives the signature as

collection_select(object, method, collection, value_method, text_method,
options = {}, html_options = {})

I''m not sure, however, if I need to place the desired code in
"options" or
"html_options".  I''m sure I could just figure it out through
trial and
error, but is there some resource which explains the difference between
options and html_options, and gives examples of each?

Thanks
Daniel